A drainage catheter or stent is widely recognized as an efficient and effective device for treating an obstructed body cavity, such as the ducts of the biliary tree or a ureter. These stents are used to bypass and drain an obstructed lumen and can be configured for long-term positioning within the lumen. It should be understood that the terms "drainage catheter" and "stent" can be used interchangeably with reference to these applications.
While drainage catheters are highly useful, proper placement of the drainage catheter often is a difficult and time-consuming procedure. Typically, an endoscope is first placed into the body cavity and positioned at the proper anatomical area. In this regard, a distal end of the endoscope is placed in close proximity to the desired area of drainage catheter placement. If necessary, a pre-dilating device is directed through the distal end of the endoscope to dilate the stricture. The dilating device is removed from the endoscope and replaced by a guidewire. Then, a guide catheter is placed over the guidewire and positioned near the stricture. The drainage catheter or stent is placed over the guide catheter until a proximal end of the drainage catheter is beyond a proximal end of the guide catheter. A push catheter is then placed over the guide catheter until a distal end of the push catheter abuts the proximal end of the drainage catheter. The drainage catheter is then pushed via the push catheter down the length of the guide catheter until the drainage catheter reaches the desired body cavity location. At this point, the drainage catheter is manipulated via the push catheter to secure the drainage catheter within the stricture.
Once properly positioned, the guide catheter and guidewire are removed from inside of the push catheter and the drainage catheter. The push catheter remains in place to prevent movement of the drainage catheter during removal of the guide catheter and guidewire.
Every effort is made to secure the drainage catheter at the proper location within the body cavity. However, there are times when the drainage catheter is placed too far into the body or migrates to a less desirable location in which case there are several time-consuming secondary procedures available to correctly position the drainage catheter. These may include placing the endoscope back into the body and directing a tool into the endoscope to grasp the drainage catheter and pull it back into position. However, it is not possible to retract the drainage catheter with the push catheter because retraction of the push catheter simply pulls the push catheter away from the drainage catheter.
In addition to the difficulties associated with drainage catheter repositioning, there are also difficulties associated with guidewire positioning. Specifically, it is sometimes difficult to maintain the position of the guidewire in the patient while the delivery system is advanced along the guidewire. Typically, two people are required to deliver a drainage catheter, one person to hold the scope handle and feed the delivery system, another person to hold the hub of the delivery system and pull on the guidewire as the delivery system is advanced. If these two operations are not synchronized, the guidewire position inside the patient may be compromised.
Drainage catheters are highly beneficial devices from a clinical stand point. However, the procedures involved in positioning or re-positioning a drainage catheter are very time-consuming and leave little room for error. Therefore, a substantial need exists for an improved drainage catheter delivery system to address these shortcomings.